Metal candle



1965 L. M. VAUGHT 3,200,745

METAL CANDLE Filed Nov. 20, 1963 WWQX/QQQW INVENTOR. L eonaro M. l ouyh 7 HTTORNEY United States Patent Ofi ice I seams Patented Aug. 17, 1965 3,200,745 METAL CANDLE Leonard M. Vaught, Lake Jackson, Tex., assignor to The Dow Chemical Company, Midland, Mich, a corporation of Delaware Filed Nov. 20, 1963, Ser. No. 325,187 Claims. (Cl. 102-373) This invention relates to an improved candle, and more particularly to a metal candle containing magnesium.

It is an object of the present invention to provide a practical, relatively long-burning candle which will produce substantially constant intensity light. '7

Other objects and advantages of the present invention will become apparent in the course of the following specfication and claims, when taken in conjunction with the appended drawings in which:

FIGURE 1 illustrates a candle in accordance with the present invention;

FIGURE 2 illustrates a particular embodiment of the present invention employing a support rod; and

FIGURE 3 illustrates an embodiment of the present invention employing a hollow core.

Candles of the present invention generally comprise a thin-walled tube 10 having metal particles or chips 11 packed therein. At one end of the candle may be positioned a suitable igniting material 12. Generally, the end of the candle which is ultimately the bottom is sealed by any suitable means, such as a sheet of the tube material. A feature of the candles of the present invention is the fact that no chemical exidizing agent is needed. Oxygen for combustion is obtained solely from the atmosphere.

Candles of the present invention are particularly useful for outdoor illumination such as lawn parties emergency lighting, and the like.

In accordance with the present invention, magnesium or aluminum particles or chips are positionedin 'a thinwalled magnesium or aluminum tube. For operability it is critical that magnesium be present as the predominant material in either the tubing or in the particles or chips, and may be present in both. Combinations of magnesium and aluminum particles or chips are suitable, as are particles or chips of magnesium-aluminum alloys. Magnesium or magnesium alloy tubing may be used with the above combinations of particles or chips.

Preferably, a fuel mixture containing from about 80 to about 90 weight percent magnesium chips and from about to about 10 weight percent aluminum chips is packed in an aluminum or magnesium tube.

The particles or chips should preferably be packed to give a bulk density in the candle of from about 0.5 to about 1.25 grams per cubic centimeter (gm./cc.). Lower bulk densities generally result in insuflicient surface contact, thereby causing difiiculty in preheating and combos tion propagation. Greater bulk densities generally result in insuflicient breathing space with consequent impaired uniformity of combustion and light emission.

Candles in accordance with the present invention may be of any practical size, with one quarter inch diameter being an effective minimum diameter.

V/hen candles having a relatively great length to diameter ratio (greater than about 6:1) are to be used, it is generally advantageous to employ a support rod 14. A support rod may be employed in smaller candles also, if desired. The support rod 14 is preferably of a material (such as a high temperature steel wire or rod) which does not markedly weaken at temperatures near the combustion temperature. Ordinarily, the support rod will run the entire length of the candle. If desired, the support rod may be extended beyond the bottom of the candle, thereby also serving as a means for holding or mounting the candle in use. The rod may alternatively or additionally be extended out the top of the candle to serve as a handle, if desired. Functionally, the support rod tends to hold ash and molten metal in place, thereby promoting smooth burning.

When the diameter of candles exceeds about three inches, the light output efficiency (candlepower) tends to decrease due to difiiculty in supplying oxygen to the central portion of the candle. Thus, when the candle diameter exceeds about three inches, it is desirable to provide a centrol hollow core 15. To provide a hollow core, tWo tubes of materials as described above and having different diameters are positioned concentrically and the annular space between them filled with suitable metal particles or'chips (fuel). Preferred maximum annular distance between inner and outer tube is about three inches. A greater fuel thickness would tend to initiate the same problems which make the hollow core desirable. An an nular space as low as one quarter inch in thickness is operative.

Particles or chips useful in the candle of the present invention are preferably of irregular shape such as would be obtained as scrap from a turning, machining, or scalping operation. Maximum dimension for particles or chips suitable in the present invention is about one-eighth inch through the smallest. cross section; Maximum size useful particles are those which will be retained on a 10 mesh screen (+10 mesh U.S. standard sieve); Particles or chips larger-than the maximum size above defined will not burn with suflicient uniformity since oxygen will not easily reach the central portions thereof. When par ticles which will pass through a 10 mesh screen (10 mesh) are employed, insufficient breathing space is maintained within the body of the candle and combustion and light emission will not be of the desired uniformity and intensity.

Outer tubing used to contain the particles or chips may have a thickness of from about 0.003 to about 0.125 inch. In general it is preferred that the thinnest tube, consistent with support requirements, be employed. Longer candles generally require thicker tubes than short candles. Inner tubing used to provide a hollow core is generally the same thickness as the outer tubing, but may be different, if desired, so long as the above limits are observed.

As a starting or igniting material, magnesium foil, sodium nitrate, or the like may be positioned at the end of the candleto be lighted. Thus, ignition may be accomplished by ordinary matches. Once the magnesium foil, sodium nitrate, or the like is ignited, the flame will propogate to the remainder of the candle. Fuses or friction sensitive caps, of the type used in railroad flares, and the like, may also be employed. Ordinarily, the use of friction sensitive caps obviates the need for matches or other flame type ignition devices.

A better understanding of the present invention may be obtained in light of the following examples which are set forth to illustrate, and are not to be construed to limit, the present invention.

Example 1 An aluminum tube eighteen inches long, one inch in outer diameter and having a wall thickness of 0.003 inch was filled with magnesium slabface scalping chips. The chips have average dimensions of about 0.25 x 0.03 x 0.25-0.50 inch and were compacted in the tube to give a bulk density of about 0.87 gram per cubic centimeter. A one-eighth inch diameter steel wire rod was positioned centrally the length of the tube. A small amount of NaNO was positioned on top of the chips in the candle and ignited with a match.

The candle burned smoothly in a horizontal plane from top to bottom in a period of 54 minutes. Uniformly white light of about 225 apparent candle-power was pro duced throughout the burning of the candle.

Example 2 A seven inch long candle was prepared by positioning 4 and mixtures and alloys thereof, and having a wall thickness of from about 0.003 to about 0.125 inch, said metal fuel comprising particles of a metal selected from aluminum, magnesium, and mixtures and alloys thereof, said 5 articles havin" a minimum size of mesh and a maxia 3.5 inch diameter by 0.006 1nch thick aluminum tube p a b a mum slze such that thv minimum cross-sectional dimenconcentrically within a 5 inch diameter by 0.003 inch tlnclr sion is no Greater than one ei hth inch said m tall rti 1 aluminum tube. The space between the tubes was filled having a g dp .5 d1 f es with 85 weight percent magnesium Grignard chips and b o y i e 9 cu to Weight percent aluminum Grignard chips. Bulk density 0f 10 3. E i per cu lc.cemimetel and said metal the compacted chips Was about 057 gram per Cubic Centi re emg urt er characterized 1n that at least one of said meter. A small amount of NaNO was positioned on elements conslsts predommanfly of magnaslum' top of the chips in the candle and ignited with a match. A metal candle conmnsmg two Flemfmtsr a metal Burning of the entire lfingth of the candle took about tube and a metal fuel positioned therein, said metal tube r: 18 mmutes, and a Whlte light of about 2100 apparent 15 be ng oiametal selected from aluminum, magnesium, and candlepower was pmduced mixtures and alloys thereof, and having a wall thickness of Example 3 from b mt 0.003 to about 0.125 inch, said metal f l comprising from about 80 to about 90 weight percent Metal candles were prepared in substantially the magnesium chips and from about 20 to about 10 weight manner described above in Examples 1 and 2. The 20 percent aluminum chips, said chips having a minimum candles Were ignited and burning rates and apparent size of +10 mesh and a maximum size such that the minicandle power measured. Pertinent representative data mum cross-sectional dimension is no greater than oneare tabulated below: eighth inch, said chips having a bulk density in said can- Fuel Burning Apparent Tnbe Material Wall x Outer Rate, Candle- Remarks Diameter (in.) Bulk inches power Material" Density 1 hour (gm-l Mgy 0,065x 1 Mg Grignard Chip 0.54 35.5 320 Ver ood l ht. Mg, 0.065 x 1.25 M1; la f p, 50 6 30.0 260 Uniioim biir nin candle.

MAbGrign-nli d Chip. 0 7 A1, 0.0031; 1.25 g oars inning 3 18.0 200 Ver s thb Al, 0.003 x 5 (outside tube), Mg Slabiace Scalp... 0.60 19. 0 1, 500 Ver; g ii lighii 0.006 x 3.5 (inside tube). Mg, 0.065 x 1.25 Softwo Sawdust 3 60. 0 320 Considerable gas, yellow 1' ht,l Mg, 0.125 x 1.25 -100 M s F P w/d n.-. wo iild n l?%l l r i'l Cardboard, 0.125 x 2 Mg S a Scalp 5 5 50 Yellow light, cardboard burned at greater rate than chips.

See the following table:

Material Approximate dimensions (inches) Mg Grignard Chips 0.13 x 0.016 1: 0.1250375 Mg Slabface scalping Chips 025 x 0.03 x 0.25-0.50 Al Grignard Chip 0.143 x 0.017 x 0.375-1 0 Mg Coarse turnings 0.5 x 0.075 x 0.25l.0

Example 4 In substantially the manner described in the foregoing examples, a 24 inch long magnesium tube having an outer diameter of 1.0 inch and a wall thickness of 0.005 inch was filled with aluminum chips and ignited. Burning progressed smoothly at a uniform rate and steady White light was emitted.

Various modifications may be made in the present invention without departing from the spirit or scope thereof, and it is to be understood that I limit myself only as defined in the appended claims.

I claim:

1. A metal candle comprising two elements, a metal tube and a metal fuel positioned therein, said metal tube being of a metal selected from aluminum, magnesium, and mixtures and alloys thereof, and having a wall thickness of from about 0.003 to about 0.125 inch, said metal fuel comprising particles of a metal selected from aluminum, magnesium, and mixtures and alloys thereof, said particles having a minimum size of +10 mesh and a maximum size such that the minimum cross-sectional dimension is no greater than one-eighth inch and said metal candle being further characterized in that at least one of said elements consists predominantly of magnesium.

2. A metal candle comprising two elements, a metal tube and a metal fuel positioned therein, said metal tube being of a metal selected from aluminum, magnesium,

dle of from about 0.5 to about 1.25 grams per cubic centimeter.

4. A metal candle comprising a one inch diameter by 0.003 inch thick aluminum tube and a metal fuel positioned therein, said metal fuel comprising magnesium slabface scalping chips having a bulk density within the candle of about 0.87 gram per cubic centimeter, said candle also having a one-eighth inch steel wire rod positioned substantially centrally the length of the candle.

5. A metal candle comprising two elements, one of said elements being a pair of metal tubes of diiferent diameters and the other of said elements being a metal fuel, the smaller diameter tube being positioned substantially concentrically within the larger diameter tube, thereby to provide an annular space at least of one quarter inch between said tubes, said metal tubes being of a metal selected from aluminum, magnesium, and mixtures and alloys thereof, and having wall thickness of from about 0.003 to about 0.125 inch, said metal fuel comprising particles of a metal selected from aluminum, magnesium, and mixtures and alloys thereof, said particles having a minimum size of +10 mesh and a maximum size such that the minimum crosssectional dimension is no greater than oneeighth inch, said metal particles having a bulk density in said candle of from about 0.5 to about 1.25 grams per cubic centimeter, said metal candle further characterized in that at least one of said elements consists predominantly of magnesium. i

6. A metal candle comprising a 3.5 inch diameter by 0.006 inch thick aluminum tube positioned concentrically within a 5 inch diameter by 0.003 inch thick aluminum tube, thereby to form an annular space between said tubes, the spaces between said tubes being filled with about 85 Weight percent magnesium Grignard chips and about 15 Weight percent aluminum Grignard chips having a bulk density within the candle of about 0.57 gram per cubic centimeter.

7. A metal candle comprising one inch diameter by 0.065 inch thick magnesium tube and a metal fuel positioned therein, said fuel comprising magnesium Grignard chips having a bulk density within said candle of about 0.54 gram per cubic centimeter.

8. A metal candle comprising a 1.25 inch diameter by 0.065 inch thick magnesium tube and a metal 'fuel positioned therein, said metal fuel comprising fifty Weight percent magnesium slabface scalping chips and fifty Weight percent aluminum Grignard chips, said chips having a bulk density Within said candle of about 0.63 gram pe cubic centimeter.

9. A metal candle comprising a 1.25 inch diameter by 0.003 inch thick aluminum tube and a metal fuel positioned therein, said metal fuel comprising magnesium coarse turnings having a bulk density Within said candle of about 0.73 gram per cubic centimeter.

10. A metal candle comprising a 3.5 inch diameter by 0.006 inch thick aluminum tube positioned concentrically within a 5 inch diameter by 0.003 inch thick aluminum tube, thereby to form an annular space between said tubes, the space between said tubes being filled With magnesium slabface scalping chips having a bulk density within said candle of about 0.60 gram per cubic centimeter.

References Cited by the Examiner UNITED STATES PATENTS 494,440 3/93 Pierce 102'-37.8 2,398,287 4/46 Christie 102-90 2,791,178 5/57 Thompson 10290 XR 3,094,445 6/63 Busk et a1 67 21 X 3,110,259 11/63 Van Dersarl 102-37.8

EDWARD J. MICHAEL, Primary Examiner.

' CHARLES J. MYHRE, Examiner. 

1. A METAL CANDLE COMPRISING TWO ELEMENTS, A METAL TUBE AND A METAL FUEL POSITIONED THEREIN, SAID METAL TUBE BEING OF A METAL SELECTED FROM ALUMINUM, MAGNESIUM, AND MIXTURES AND ALLOYS THEREOF, AND HAVING A WALL THICKNESS OF FROM ABOUT 0.003 TO ABOUT 0.125 INCH, SAID METAL FUEL COMPRISING PARTICLES OF A METAL SELECTED FOM ALUMINUM, MAGNESIUM, AND MIXTURES AND ALLOYS THEREOF, SAID PARTICLES HAVING A MINIMUM SIZE OF +10 MESH AND A MAXIMUM SIZE SUCH THAT THE MINIMUM CROSS-SECTIONAL DIMENSION IS NO GREATER THAN ONE-EIGHTH INCH AND SAID METAL CANDLE BEING FURTHER CHARACTERIZED IN THAT AT LEAST ONE OF SAID ELEMENTS CONSISTS PREDOMINANTLY OF MAGNESIUM. 